A U.S. district court judge delivered a major setback to Alcatel-Lucent on Monday by setting aside a jury's $1.5 billion judgment against Microsoft in a patent infringement lawsuit over digital music technology.

Alcatel-Lucent's lawsuit against Microsoft had produced the largest patent judgment on record.

The case centered on origins of the MP3 standard.

The Windows Media Player software, part of Microsoft's basic operating system, plays audio files using the MP3 standard, the most common method of distributing music on the Internet.

The ruling could have an impact on Apple, the dominant maker of digital music hardware and software, as well as hundreds of other companies that use the standard.

Judge Rudi Brewster of U.S. District Court in San Diego wrote in a 43-page order that the jury's damage award in February could not stand because one of the two patents on which the case focuses was not infringed by Microsoft.

He also noted that ownership of the second disputed patent was questionable, and a retrial may be needed to resolve that matter.

Alcatel-Lucent immediately said it intended to appeal the ruling.